"B" Oval: Faceting Design Diagram


Detailed information and guide for Faceting Design Diagrams. This facet design is called a " "B" Oval". The breaks are high, but this should be easy to set.

0

Tourmaline (Achroite, Dravite, Rubellite, Indicolite, Verdelite, Siberite)

"B" Oval (B6.JRG)
By Jeff R. Graham
Copyright 1999
80% Light Return
Angles for R.I. = 1.62
81 facets + 16 facets on girdle = 97
2-fold, mirror-image symmetry
96 index
L/W = 1.303 T/W = 0.762 T/L = 0.585
P/W = 0.588 C/W = 0.199
H/W = (P+C)/W+0.02 = 0.807
P/H = 0.728 C/H = 0.247
Vol./W^3 = 0.402

Addition # 5 - The breaks are high, but this should be easy to set on the short ends. Cut to center point, then girdle to meet P1, then breaks. Cut in R.I 1.62 to 1.76 (89.4%) with no changes, light material is best.

 


Random - Cosine - ISO

Detailed faceting instructions by Jeff Graham available at The Rock Peddler


Jeff R. Graham

The late Jeff Graham was a prolific faceter, creator of many original faceting designs, and the author of several highly-regarded instructional faceting books such as Gram Faceting Designs.

Never Stop Learning

When you join the IGS community, you get trusted diamond & gemstone information when you need it.

Become a Member

Get Gemology Insights

Get started with the International Gem Society’s free guide to gemstone identification. Join our weekly newsletter & get a free copy of the Gem ID Checklist!